Last year, Wyatt Doyle caught five wild pallid sturgeon in the Missouri River. And he thinks it will be years before scientists understand how the endangered fish and other species respond to the creation of new habitats on the river.
Doyle and his teams with the U.S. Fish and Wildlife Service monitor shallow-water habitats built by the U.S. Army Corps of Engineers to comply with the Endangered Species Act, which pallid sturgeon fall under.
The corps must return the river to some semblance of its natural state. Shallow-water habitats are only one facet of the recovery program. Another aspect — a spring rise — is hotly debated, and the corps must have an operating plan in effect by March 1 to make that happen. A stakeholder group has been designing plans to handle a spring rise and will next meet Aug. 19 in Sioux Falls, S.D.
“We would love to have a consensus-based product by the end of August,” said Craig Fleming, a corps fishery biologist. “In light of the pallid sturgeon, it’s not a question of whether we have one (a rise) or not,” Fleming said. “It’s a question of how big and when.”
The group also faces issues such as crop loss, barge traffic, endangered species and exposing native burial sites.
At the moment, upstream releases are not managed to create either a spring rise or a summer draw-down, both of which would create diverse habitats. The corps manages releases from reservoirs to ensure an adequate channel for navigation.
While flow issues are still unresolved, the corps has moved forward by constructing a diversity of shallow-water habitats. The corps made more than 1,200 acres of side-channel chutes and has put notches in dikes and banks since early 2004, spending $15 million.
The corps plans to create 20,000 acres of shallow-water habitat by 2020, with continued monitoring for a minimum of 30 to 50 years. The entire shallow-water habitat side of the Missouri Recovery Program will cost about $400 million.
The corps constructed little habitat this year.
“We took a step back to see how it was working,” corps project manager Mike George said. This will be the only year that the corps can afford to slow habitat creation activities and still meet the 2010 deadline of 33 percent of the 20,000 total acres, George said.
Research hydrologist Robert Jacobson of the U.S. Geological Survey’s Columbia Environmental Research Center said the corps is practicing adaptive management of the river — learning from outcomes and modifying policies during the process.
Jacobson said scientists need to learn how to interact better so that engineers can use their input and research correctly. Poor communication between agencies led to inefficiencies in the past.
The corps relies on a variety of state and federal agencies to conduct physical and biological monitoring of the habitat projects.
Jacobson now passes along data and results from a decade of studying the Lisbon Bottom chute, which was naturally carved between Boonville and Glasgow after flooding in the mid-1990s.
At one point, the chute carried up to 20 percent of the river’s flow and provided a variety of aquatic and terrestrial habitats. The corps restricted the chute’s flow in 1999, however, fearing it would hurt the navigation channel.
Jacobson is more optimistic about positive results from side channels than from notched banks or dikes because channels are the only habitat that can have a gravelly river bottom, or substrate. The other notched habitats produce more of a silty substrate, but gravel substrates are important for spawning. Specific pallid sturgeon spawning sites are not known, but gravelly substrates are believed to be a prime location, Jacobson said.
The corps has notched dikes since the 1980s in hopes of creating more sandbars behind the dikes, but Jacobson said those projects have not been very successful.
Locally, notched banks have been made at Eagle Bluffs and Diana Bend conservation areas and look like large, semi-circular cutouts. Jacobson is skeptical of their potential because their habitat value relies heavily on how much erosion occurs, which is unpredictable.
Doyle of the Fish and Wildlife Service thinks there would be irreplaceable losses without a well-implemented spring rise. The rises need to be coordinated with times, temperatures and many other factors for best results.
“The Missouri River naturally has two rises,” Doyle said. “The first from snow melt on the plains in the Midwest and the second from mountain runoff in the summer.”
The first rise is vital to cleaning gravel bars, which are spawning beds. Doyle believes that the rise also acts as a hormonal trigger to let fish know it is time to spawn.
Fish then spawn on the gravely substrate and the eggs and larvae attach themselves to it. Predators know where to find this easy treat, which is why the second rise is also important.
The second rise washes the eggs and larvae off of the gravel and moves them downstream, making them harder to find by predators. Additionally, the high water creates more turbidity, or murkiness, that acts as a natural camouflage.
Both rises also create an array of shallow-water habitats through the variation of depths and velocities.
Doyle said the rises are important because the juvenile stage is the most difficult to survive. Pallids first spawn after 10 or 12 years, and only once every several years after that. Doyle compares that with a bluegill, which produces 25,000 eggs three times a year.
As the debate about a spring rise continues, Doyle’s crews are on the river collecting data. Andy Starostka leads biological monitoring for Doyle on six bends between the Grand and Osage rivers: three long gradual bends and three sharp curves to reflect habitat diversity.
Fleming, who coordinates overall habitat assessment, hopes to be monitoring 48 bends along the 800-mile stretch between Gavins Point Dam and the confluence by next year. Having spent $1.4 million thus far, Fleming anticipates an annual $3 million budget to continue monitoring all chosen sites.
“They’ve shown value,” Fleming said about the habitats. “There were chutes created in the past, and juvenile pallid sturgeon have been captured in those chutes. In 10 to 15 years, we should have a pretty good idea of what works and what doesn’t. We’ll have a more refined creation and monitoring effort.”